Influence of methods of selection of parents by the index of similarity of antigens in blood groups on weight and linear growth of bulls

Abstract

In solving the problem of qualitative improvement of meat breeds, an important place is occupied by the improvement of methods of practical use of existing methods of selection of parental pairs using histocompatibility antigens, polymorphic proteins and blood group systems. The purpose of the work is to determine the effect of homogeneous and heterogeneous selection of parental pairs by blood group factors on the weight and linear growth of Ukrainian beef bulls. Ukrainian meat breed is bred using four breeds and is characterised by high variability in polymorphic traits. The type of selection of parents was determined by the index of antigenic similarity (ras) of antigens of the B blood group system of cattle. To calculate the index of antigenic similarity of parents, the formula of D.A. Zhivotovskiy and A.M. Mashurov was used. The selection was considered homogeneous if the parents’ ras ≥ 0.268, and heterogeneous if ras ≤ 0.267. It is proved that bulls that come from parents with higher ras prevail in the test by average daily gain and have a higher live weight. For ras in parents over 0.268, animals tend to improve growth rate by 8 months of age. This trend continues after weaning. Bulls sired by parents with ras up to 0.267 have better average daily gains in the period from 15 to 18 months, which indicates their lower precocity. According to the index of antigenic similarity of parents over 0.268, animals are better in terms of meat forms at the age of 15 and 18 months. At 15 months of age, bulls obtained from homogeneous selection for ras have smaller height measurements, the better developed front part of the body in terms of chest width and depth, and longer torso and hindquarters. Homogeneous selection of parental pairs according to the index of similarity of antigens of the B blood group system improves the weight growth and expressiveness of meat forms in bulls of the Ukrainian beef breed